Embattled British Prime Minister Keir Starmer says he did not know the "depth and darkness" of the relationship Peter Mandelson had with convicted sex offender Jeffrey Epstein before he appointed him as ambassador to the US.
Lord Mandelson lost his ambassadorship in September, after the release of some of the Epstein files.
He resigned from the British Labour Party on Monday, following further revelations about his relationship with the convicted sex-offender.
Mr Starmer apologised to Epstein's victims and said that he regretted the decision to appoint Lord Mandelson to such an important position in December 2024.
It was public knowledge before he was appointed to the role of ambassador that Lord Mandelson had a relationship with Epstein.
Mr Starmer said that, when he asked Lord Mandelson questions about the nature of his relationship with Epstein, the former Labour strategist lied.
"None of us knew the depth and darkness that relationship," he said.
"He portrayed Epstein as someone he barely knew, and when it became clear that was not true, I sacked him."
Starmer under pressure
Bank records released by US authorities last week appear to show that in 2009, Lord Mandelson, who was then UK business secretary, forwarded an economic briefing to Epstein intended for then-Prime Minister Gordon Brown.
Emails released by the US Department of Justice also indicate that Lord Mandelson appears to have tried to secure a tour of Downing Street for a Russian model linked to Epstein while he was business secretary in 2010.
The emails, first reported by Times, suggest that the tour did not happen because the schedules did not align.
Mr Starmer's leadership is under increasing pressure amid the scandal and he has been asked to release the vetting advice he received when Lord Mandelson was being considered as ambassador.
"I understand the strength of public anger, I want to be able to release those documents as quickly as possible, I wanted to release them yesterday," he said.
"But police advised that releasing them now could jeopardise an investigation."
Earlier in the week, Mr Starmer ordered an inquiry into the ties between Lord Mandelson and Epstein during the politician's time as a government minister.
"I want to say this to the victims: I am sorry," he said.
"Sorry for what was done to you, sorry that so many people with power failed you, sorry for having believed Mandelson's lies and appointing him."
Mr Starmer has previously said that Lord Mandelson should be stripped of his title as a lord and no longer sit in the House of Lords.
The review, which will be led by Cabinet Secretary Chris Wormald, comes after newly released US documents revived scrutiny of Lord Mandelson's relationship with the convicted sex-offender.